Graphene's Latest Cousin: Plumbene Epitaxial Growth on a “Nano WaterCube”

Abstract

While theoretical studies predicted the stability and exotic properties of plumbene, the last group‐14 cousin of graphene, its realization has remained a challenging quest. Here, it is shown with compelling evidence that plumbene is epitaxially grown by segregation on a Pd1−xPbx(111) alloy surface. In scanning tunneling microscopy (STM), it exhibits a unique surface morphology resembling the famous Weaire–Phelan bubble structure of the Olympic “WaterCube” in Beijing. The “soap bubbles” of this “Nano WaterCube” are adjustable with their average sizes (in‐between 15 and 80 nm) related to the Pb concentration (x < 0.2) dependence of the lattice parameter of the Pd1−xPbx(111) alloy surface. Angle‐resolved core‐level measurements demonstrate that a lead sheet overlays the Pd1−xPbx(111) alloy. Atomic‐scale STM images of this Pb sheet show a planar honeycomb structure with a unit cell ranging from 0.48 to 0.49 nm corresponding to that of the standalone 2D topological insulator plumbene.

2D Crystal–Based Fibers: Status and Challenges

“…These bubbles were observed by STM, and a clear honeycomb structure of 0.48 nm was observed. At present, there is only one report on the preparation of plumbene, and there is no report on its application …”

Emerging Applications of Elemental 2D Materials

“…i) Reproduced under the terms of the CC‐BY 3.0 Attribution 3.0 Unported License ( https://creativecommons.org/licenses/by/3.0/) . Copyright 2018, IOP Publishing Ltd. j–n) Reproduced with permission . Copyright 2019, Wiley‐VCH.…”

“…Spin–Orbit Coupling : Group IV 2D analogues with semimetallic band structure have been predicted to exhibit some degree of spin–orbit coupling (SOC) leading to opening of a small bandgap around Dirac cone, which increases with their atomic number, i.e., C < Si < G < Sn, giving rise to possibility for realization of the quantum spin Hall effect (QSHE) . Heavier elemental 2D materials within the group IV, V, and VI elements (plumbene, bismuthene, selenene, and tellurene) have also been shown to exhibit a large spin–orbit coupling . In group IV elements, silicene is predicted to have a spin–orbit gap of 1.55 meV, while germanene is predicted to have one of 23.9 meV in freestanding form.…”

Two‐dimensional materials of group‐IVA boosting the development of energy storage and conversion

“…A, Low‐energy electron diffraction pattern, (B) large‐scale scanning tunneling microscope (STM) image, and (c) atomically resolved STM image of plumbene. Reproduced with permission: Copyright 2019, Wiley 39 …”

“…Although plumbene is theoretically predicted to exist, its realization remains a big challenge. The tremendous progress in plumbene was recently made by Yuhara et al 39 They epitaxially grew the planar honeycomb structure of plumbene on a Pd 1 − x Pb x (111) alloy surface by segregation ( Figure 9). Its average size could be dynamically tuned with the Pb concentration of the Pd 1 − x Pb x (111) alloy.…”